When resection of a segment of the mandible is indicated for carcinoma of the oral cavity, immediate reconstruction of the resected mandible should be considered. Resection of the body of the mandible produces one of the most significant aesthetic and functional deformities in surgery for oral cancer. The aesthetic appearance of the patient is unacceptable, and the functions of speech and mastication are seriously compromised. The impact of resection of the anterior arch is even more devastating. Many patients drool saliva after resection of the anterior arch of the mandible and have significant swallowing difficulties. The optimal method of reconstruction of the resected mandible at the present time is with a fibula free flap. Microvascular composite free tissue transfer is the state of the art in reconstruction of major composite defects following resection for advanced carcinomas of the oral cavity. However, caution must be exercised in selecting patients who are candidates for such a major reconstructive effort. The selection of patients should take into account the age and medical condition of the patient, the size of the surgical defect, resultant disability from ablative surgery, disability at the donor site, and the overall prognosis.